Boston Scientific's Watchman stroke-fighting device wins overwhelming FDA panel support

Boston Scientific's Watchman antistroke device won overwhelming backing from an FDA panel of experts.--Courtesy of Boston Scientific

After an up-and-down development path, Boston Scientific ($BSX) gained a crucial second chance for its implant designed to help prevent strokes in atrial fibrillation patients. An FDA advisory panel has overwhelmingly endorsed the Watchman device for approval, potentially boosting its chances before regulators.

As Bloomberg and others reported, the agency's Circulatory System Devices Panel agreed 13-1 after a daylong meeting Dec. 11 that Watchman's benefits outweighed any risks, and that it was both safe and effective to use the device to close off the left atrial appendage to catch blood clots before they migrate up to the brain and cause strokes.

The panel's recommendations aren't binding, but the FDA's final decision is generally in tandem. There are exceptions, however, and Watchman has been among them. Bloomberg noted that the FDA rejected the device in 2010, in part because of a high rate of complications, despite a panel endorsement. Regulators asked for a new clinical trial, which became PREVAIL, and the study helped reduce the 7-day serious complication rate almost by half. But PREVAIL missed its second efficacy endpoint, with results suggesting that Watchman wasn't much better than the standard of care: warfarin or other blood-thinning drugs for stroke prevention.

Four-year follow-up data from the initial trial--Protect AF--may have been Watchman's saving grace, pointing to Watchman as scoring statistically higher than warfarin at preventing cardiovascular death, all-cause stroke and systemic embolization. The FDA panel said that the long-term data mattered more, according to the Bloomberg story.

Other companies are working hard to bring similar devices toward approval, including St. Jude Medical ($STJ), with its Amplatzer plug. But analysts including Larry Biegelsen of Wells Fargo predicted Boston Scientific will get there first, the article explained, with approval expected by the 2014 second quarter. Boston Scientific predicts Watchman could be part of a $500 million market once it is approved and would likely be first out of the gate in the U.S.

Boston Scientific snatched up the Watchman technology when it grabbed Atritech in 2011 for $375 million, and the product is a big part of the Massachusetts device giant's broader turnaround plan.

- here's the full Bloomberg story
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